iPhone 3GS Smokes Competition in OpenGL Benchmarks

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The new Apple iPhone 3GS feels fast, but it’s always good to see your feelings confirmed with hard numbers. Laszlo Kishonti, creator of the JBenchmark benchmark suite that I use on all Java-based phones, managed to install his GLBenchmark OpenGL benchmark onto both an iPhone 3GS and iPhone 3G (please, don’t ask how) and watched the new model smoke the competition on low-level tests.

According to various independent sources (because Apple—no shock—isn’t telling) the iPhone 3GS is one of only two consumer smart phones running an ARM Cortex-A8 processor, a significant step beyond the ARM11 in the previous iPhone. The 3GS also uses the PowerVR SGX graphics core, a bump above the PowerVR MBX in the iPhone 3G.

The Cortex-A8, according to ARM, gets 2 DMIPS/MHz by using dual, symmetric, in-order pipelines; a dedicated L2 cache; and NEON, a dedicated media accelerator unit with at least double the performance of the equivalent unit on ARM11 chipsets. (The DMIP, or Dhrystone MIP, is a measure of computing power.) The PowerVR SGX, according to its maker Imagination Technologies, uses shader-driven, tile-based deferred rendering and supports OpenGL ES 2.0; the previous version didn’t support shaders or OpenGL ES 2.0.

Kishonti encountered some snags when benchmarking the 3GS. The iPhone maxes out at 60 frames per second, which initially capped the 3GS’s performance on some benchmarks. Also, Kishonti’s current benchmarks test OpenGL 1.0 and 1.1 performance. The iPhone 3GS’s GPU runs OpenGL ES 2.0, emulating many 1.1 features using generic shaders, which limits performance there. That’s why the 3GS’s overall result on an OpenGL ES 1.1 benchmark may look unusually slow.

But dig into the low-level tests and you see some fearsome power. The 3GS blows away both the earlier 3G and the second-most-powerful phone in Kishonti’s benchmark list, the Nokia N95 8GB, on many individual tests, sometimes by a huge amount. In low-level fill and texture filter tests, for instance, the iPhone 3GS’s new GPU really comes into play. The 3GS got a score of 5.2 million triangles/sec in a linear texture filter test, for instance, where the iPhone and Nokia N95 both got between 555-600,000 triangles.

On pure CPU tests, the 3GS delivered double the floating-point performance of the N95, and considerably more than the 3G. The 3GS fell short only on swapbuffer speed, which was the same as the 3G and slower than the Nokia N95 8GB.

When OpenGL ES 2.0 benchmarks come out, they’ll further reflect the iPhone 3GS’s advantages, Kishonti said. You can see his full results here.

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